The application generally relates to automated methods for controlling a path of a vehicle. The application relates more specifically to automatically controlling a steering system of an agricultural or construction vehicle along a predetermined swath path.
Methods for automatically controlling or steering an agricultural or construction vehicle via global positioning system (GPS) or local position detection systems are known. Such vehicles may be guided along a predetermined path using position sensors that communicate the vehicle position relative to the desired path to an automatic guidance controller.
Various parameters in an auto-guidance (AG) control algorithm may be adjustable by the operator to fine-tune the performance of the AG system for such aspects as the rate at which the vehicle will turn the steering system to reduce the amount of time and length of travel before the vehicle may acquire the desired path, or to reduce the margin of error with respect to the desired path. The auto-guidance parameters that may be applied in the AG control algorithm may also affect how accurately the vehicle follows the path. The path can vary from a straight line, to a curved pattern, to a circular pattern, etc. A curved path can have varying degrees of turn from a very gradual turn to a very sharp turn, subject to the limits of the vehicle's ability to make the prescribed turn, i.e., the vehicle's turning radius. The minimum turn radius that a vehicle can negotiate may in some instances be set by the vehicle operator, or in other instances, the limit may be automatically calculated by the AG control algorithm software based on the vehicle type entered into the software.
A single value for the operator adjustable AG parameters may not provide a desired performance level or accuracy for all of the variations in operating conditions that the vehicle is likely to encounter. It is difficult for an operator to constantly change the AG parameters in response to changing field conditions. For example, one value of the parameter may be adequate for a straighter portion of a curved path, yet unacceptable for a sharper curved portion of the path, as the sharper curved portion introduces errors in tracking the path. Further, some AG parameters that can be adjusted require specialized equipment and personnel to access the AG algorithm in order to properly adjust or tune the AG parameter. The operator is not able to readily change these parameters to optimize AG system performance during operation of the vehicle.
Therefore, what is needed is a system and method to adaptively adjust, either automatically or manually, one or more control parameters of an AG control algorithm to more accurately follow a predetermined path or swath.